1. Field of the Invention:
The present invention relates to a multi-chip module comprising a plurality of electronic components (e.g. IC chips, resistors and capacitors) which are collectively enclosed in a resin package.
2. Description of the Related Art
A typical prior-art multi-chip module has the structure as shown in FIG. 7. The illustrated multichip module includes a substrate 90 made of epoxy resin for example. The substrate 90 is formed with a predetermined wiring pattern 92. A plurality of electronic components 91 are mounted on the substrate 90. Each of the electronic components 91 has terminals which are electrically connected, via a plurality of wires W, to respective portions of the wiring pattern 92 on the substrate 90. Terminal made of metal are soldered onto the wiring patter 92 The electronic components 91, the wires W and their bonding portions are coated with resin (not shown applied and melt thereon for insulation and protection.
According to the structure shown in FIG. 7, however, the process for making the multi-chip module is complicated because it requires the successive steps of forming the wiring pattern 92 on the substrate 90 using a metal film, and mounting the terminals 93 on the substrate 90 into conduction with the wiring pattern 92.
To solve the problem described above, JP-U-A-5-15449 and JP-A-5-29539 disclose another type of multi-chip module, which is made utilizing a leadframe as shown in FIG. 8. Specifically, the leadframe designated generally by reference numeral 94 includes a plurality of die-bonding pads 95 and a plurality of leads 96. A plurality of electronic components 91 are mounted on the die-bonding pads 95, respectively. The lead terminals 96 correspond to the terminals 91a of the electronic components 91. Each terminal 91a of the electronic components 91 is electrically connected to a respective of the lead terminals 96 via a wire W.
As shown in FIG. 9, a resin package 97 is molded to the electronic components 91 together with part of the lead terminals 96, and the lead terminals 96 are cut off the leadframe 94 to provide a multi-chip module. In the multi-chip module thus provided, the lead terminals 96 are insulated from each other and partially protrude outwardly from the resin package 97. This type of multi-chip module can be manufactured more easily than the multi-chip module of the type shown in FIG. 7
In this type of multi-chip module, however, the lead terminals 96 are provided only for electrically connecting the terminals 91a of each electronic component 91 to another member outside the resin package 97. Therefore, although the plurality of electronic components 91 are collectively resin-packaged in the multi-chip module, the electronic components 91 are not electrically connected to each other inside the resin package 97. Therefore, it is impossible to complete a desired electric circuit solely by the multi-chip module even if all electronic components necessary for completing the electric circuit are fully built in the multi-chip module. In other words, any electronic component of the multi-chip module can be electrically connected to any other component of the same module only via a wiring pattern of an external circuit board to which the module is mounted or connected. Such a need not only is inconvenient but also leads to a cost increase.
It is therefore an object of the present invention to provide a multi-chip module which is capable of completing an electric circuit without utilizing an external element or elements such as a printed circuit board.
In accordance with a first aspect of the present invention, there is provided a multi-chip module comprising metal frame segments including a plurality of die-bonding pads and a plurality of terminals, a plurality of electronic components mounted on the die-bonding pads in electrical connection to the terminals, and a resin package for enclosing the electronic components and the metal frame segments with each of the terminals partially projecting outwardly from the resin package. Selected ones of the electronic components are electrically connected to each other via the metal frame segments and wires within the resin package.
With the structure described above, selected ones or all of the electronic components are electrically connected to each other via the metal frame segments and the wires within the resin package, so that a desired electric circuit can be completed without relying on an external element or elements. Further, since the metal frame segments come from a metal frame, it is unnecessary to use an insulating substrate on which a conductor layer needs to be formed and etched to provide a wiring pattern as required for completing the intended circuitry.
Preferably, the metal frame segments may further include at least one intermediary element separate from the die-bonding pads and the terminals for electrically connecting at least one of the electronic components to at least another of the electronic components.
Preferably, the intermediary element may be electrically connected to selected ones of the electronic components via wires.
Preferably, at least one of the electronic components may be mounted to bridge between one of the terminals and one of the die-bonding pads.
Preferably, at least one of the electronic components may be mounted to bridge between selected two of the die-bonding pads.
Preferably, at least two of the electronic components may be bonded on a common one of the die-bonding pads.
In a preferred embodiment, the electronic components together with the metal frame segments constitute a protective circuit for protecting a rechargeable battery. In this case, one of the terminals may preferably have two electrode portions projecting outwardly from the resin package, whereas each of the other terminals may have a single electrode portion-projecting outwardly from the resin package.